With the development of semiconductor technology, various semiconductor elements are invented. For example, memories, transistors, and diodes are widely used in various types of electronic devices. In the development of memory technology, researchers have been trying to make a variety of types of developments and improvements, and random-access memory (ReRAM) is one of the types.
ReRAM that apply difference of resistance within the memory cells thereof for implementing the erase/program operation have advantages in terms of cell area, device density, power consumption, programming/erasing speed, three-dimensional integration, multi-value implementation, and the like over FLASH memory devices.
Generally, it is necessary to have a smaller contact size and flat contact surface for ReRAM to shrink the size of the memory. However, it would be difficult to achieve the goals mentioned above by the traditional etching process.